Final answer:
Amperage in electrical circuits is calculated by dividing the power in watts by the voltage in volts, using the formula I = P / V.
Step-by-step explanation:
The calculation of amperage (A) in electrical circuits is straightforward; it is derived from the relationship between power (P), voltage (V), and current (I). In accordance with the formula for electric power, P = IV, where P is power in watts, I is current in amperes, and V is voltage in volts. To calculate the current, we rearrange the formula to I = P / V. Therefore, amperage is calculated by dividing watts by volts.
For instance, a car's auxiliary power outlet may deliver a maximum power of 240 watts at a voltage of 12 volts. Using our formula, the maximum current the outlet can provide is I = P / V = 240 W / 12 V, which equals 20 A. This example helps us understand how electric power, measured in watts, relates to current and voltage in practical applications.